母体对小麦胚的ABA敏感性和种子休眠性的影响

种子休眠是品种穗发芽抗性的主导因素,休眠特性与母体效应和胚对ABA的敏感性均有密切关系。为了了解母体对小麦胚的ABA敏感性和种子休眠的影响,为抗穗发芽育种提供科学依据,对穗发芽抗性不同的小麦品种及它们正反交F1后代授粉后不同发育阶段的胚进行了ABA敏感性鉴定,并对收获前的籽粒发芽能力进行了测定。结果表明,在种子发育过程中,不同基因型的离体胚萌发能力存在差异,抗穗发芽品种的胚对ABA敏感性明显高于易穗发芽品种,胚对ABA的敏感性与其萌发能力关系密切,随着萌发能力的升高,胚对ABA的敏感性降低。在成熟种子中,F1的休眠性偏向于抗性亲本。尽管成熟种子和胚的休眠表现出一定的母体效应,但母体对发育至成熟过程中胚的ABA敏感性并没有影响。因而,母体对种子休眠的影响可能与胚的ABA敏感性无关。

Maternal Effect on Sensitivity of Embryo to ABA and Grain Dormancy in Wheat

Pre-harvest sprouting (PHS)is one of the most damaging diseases in rain-affected wheat (Triticum aestivum L.) crops. Grain dormancy is the dominant mechanism to inhibit PHS in cereals, proposed dormancy mechanism has focused on the regulation of (germination) by both maternal (effect) and (embryonic) (sensitivity) to phytohormone abscisic acid. To better understand this issue,maternal (effect) on ABA (sensitivity) of wheat (embryo) during seed maturation was identified by reciprocal crossing between sprouting (susceptible) and resistant cultivars, the (germination) ability of physiological mature seed was also determined. The results indicated that during seed maturation, (embryonic) (germination) abilities among genotypes were (different). ABA (sensitivity) in developing wheat (embryos) of sprouting resistant cultivars was higher than that of (susceptible) cultivars. Embryonic ABA (sensitivity) was related to its (germination) ability, the higher the (embryo) (germination) ability was, the lower the Embryonic ABA (sensitivity) was. In mature seed, seed dormancy of F_1 generation was inclined to sprouting resistant parents. There were maternal (effect) on dormancy of mature seeds and (embryos), but no (effect) on ABA (sensitivity) in developing wheat embryos. Therefore, maternal (effect) on seed dormancy might be irrelative to embryonic sensitivity to ABA.